1. Field of Invention
This invention relates to a device and a method for shaft or journal repair, specifically to such shafts or journals damaged by seizure of the bearings supporting them.
2. Description of Prior Art
Bearings that support shafts or journals routinely fail. This mechanical failure frequently scores or otherwise damages the surface of said shafts or journals to the extent that a replacement bearing will not fit the shaft or journal properly. Repairing the damaged area or replacing the shaft or journal is necessary to reestablish the necessary fit. Often the decision is made to try a repair because of the unavailability of a replacement shaft or journal, or in some cases because of the cost of the replacement. The present method of repairing shafts and journals consists of machining the damaged area, often in place, and installing a "sleeve" over the damage. This sleeve is itself then machined to obtain, as nearly as possible, the original dimensions of the damaged area. In some cases the damaged shaft or journal is removed to a machine shop for this procedure. In either case, repair or replacement, the costs are significant and the time involved can be quite long, sometimes days. The result is a loss of operation of the shaft or journal that can be costly in terms of lost production or efficiency.
A method of effecting an in-place repair using a forming device has been known in the art for some time, but it involves machining a former for each particular repair. This is inherently inefficient, as a former must be manufactured for each instance of damage, and is thereafter of use only on an area of like damage. A problem also arises with these formers often being machined improperly, and the subsequent repairs failing after a short time in service.
U.S. Pat. No. 4,936,005 to Dziurowitz (1990) discloses a clamping apparatus which can repair a damaged surface as described above, but does not consider the surface necessary for the reassembly of a bearing. U.S. Pat. No. 4,781,496 to Schuchman (1988) shows a means of resurfacing a housing, but does not address the shaft or journal itself.
A variety of other U.S. Patents attempt to address various repairs to pipes, poles, joints, couplings, and hoses. Among them, U.S. Pat. No. 5,337,469 to Richey (1994); U.S. Pat. No. 4,585,091 to Budd (1986); U.S. Pat. No. 4,358,417 to Beinhauer (1982); U.S. Pat. No. 4,268,070 to Adams (1981); U.S. Pat. No. 4,175,311 to Bunyan (1979); U.S. Pat. No. 3,491,182 to Hunder et al. ((1965); U.S. Pat. No. 2,586,640 to Furman (1947); U.S. Pat. No. 1,619,287 to Charter (1923); U.S. Pat. No. 1,445,858 to Tallman (1922); and U.S. Pat. No. 697,262 to Marcy (1902). All of these repair methods suffer from two key disadvantages:
(a) When employed as directed, they do not allow for the necessary installation of a new bearing as required by the shaft or journal. PA1 (b) As with the manufactured formers discussed earlier, most are used for a singular application, and lost to subsequent use. PA1 (a) to provide a device which is immediately sizeable to virtually any diameter shaft or journal encountered; PA1 (b) to provide a device which is re-useable after each repair encounter; PA1 (c) to provide a repair which is the same size as the undamaged portion of the shaft or journal; PA1 (d) to provide a repair which is perfectly aligned with the original axial orientation of the shaft or journal being repaired; PA1 (e) to allow for timely return to service of the repaired shaft or journal, often less than one hour from the start of the repair; PA1 (f) to provide for the in situ repair of damaged shafts or journals encountered; PA1 (g) to provide a repair surface which is consistent in feel and appearance of the undamaged portion of the shaft or journal.